An alkaline dry cell battery is a storage device for electrical power intended to provide electrical power on demand to an electrically powered device. A dry cell battery is so called because its electrolyte is in the form of a moist paste, which is therefore not capable of being spilled, since it is in a semi-solid state. The typical commercially available dry cell batteries manufactured today are constructed as a cylinder. The cathode is typically a manganese dioxide (MnO.sub.2) powder cathode, with additives, formed on the outside of the cylinder of the battery. The cathode layer is typically coated onto the interior of a nickel plated steel can. The anode, formed of powdered zinc mixed with electrolyte, is located centrally in the cylinder of the battery. The centrally located cathode surrounded by an alkaline paste containing an electrolyte base, such as potassium hydroxide (KOH). Such alkaline dry cells are not rechargeable due to the irreversible disintegration of the cathode caused by its expansion as electrical power flows from the battery.
The present invention makes use of the technology of ceramic membranes. Ceramic membranes are compositions of matter which consist of a plurality of metal oxide particles which are partially fused together to form a material which is solid, rigid, stable, but which is also porous. The porosity of the ceramic membrane can be controlled by manipulation of process conditions during its fabrication so as to create pores in any desirable range of pore sizes. Such membranes can also be made over a wide range of densities. Typically, porous metal oxide ceramic membranes are made by sol-gel processes. In such processes first metal particles are formed by a sort of inorganic polymerization/condensation from molecular precursors in a solution or suspension. The particles are maintained as partially soluble metal oxide particles in suspension by techniques such as peptization, aggressive agitation, or other similar means to prevent aggregation and resultant precipitation of larger metal oxide particles. Such a metal oxide suspension, known as a sol, then has the solvent, either water or alcohol, removed from it to create a gelified, semi-solid material referred to as a gel. The gel then has further solvent removed and then by heating or firing the gel, the particles which make up the gel are fused together to form a continuous metal oxide ceramic porous membrane material. One class of metal oxide porous ceramic membranes are disclosed in U.S. Pat. No. 5,006,248, which describes such materials with a uniquely small size range of pores therein.